Pin for artificial teeth, small rings, fusing-in wires, and the like



Patented Sept. 29, 1925 I UNITED STATES r 1,555,315 PATENT OFFICE.

WILHELM norm, or Hanan, GERMANY.

PIN FOR ARTIFICIAL TEETH, SMALL RINGS, I EU'SING-IN WIRES, AND THE LIKE.

No Drawing.

Application filed April 13, 1920. Serial No. 373,606.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. 14.,1313.)

To all whom it may conccm;

Be it known that I, WILHELM RoHN, a citizen of Germany, and resident ofHanau, Germany, have invented new and useful Pins for Artificial Teeth,Small Rings, Fusing-in Wires, and the like (for which I filed anapplication, in Germany, April 18, 1918, now Patent No.'34=8,917), ofwhich the following is a'specification.

. Technically produced metals contain, as is well known, considerablequantities of gases in solution. It is further known. that such metalswill, under favorable conditions, yield up the whole or a part-of theircontent of gas. 'This is particularly disagreeablewhen wires drawn ofsuch metals or alloys are fused into ceramic or glassy ma-' terials, asthis is, for example, necessary with the fusing-in wires conducting thecurrent to the incandescent wire for electric incandescent lamps orRontgen-ray tubes or the like, or also in fusing the pins into theporcelain body of artificial teeth. When leading-in wires are fused intoglass they will, frequently, even if' the coeflicient of heat-expansionof the wire is absolutely the same as that of the glass, be surroundedby a whole coat of vesicles enclosing the surface of the wire fused intothe-glass. According to the fusing-in process employed this coat orvesicles may consist of a few large bubbles or of a vast number ofextremely fine bubbles. It is obvious that this is not favorable for thequality, the reliability and the hermeticalquality of the fusing-in. Thesame is thecase with artificial teeth. If such an artificial tooth isbroken apart at the place where the pin, say of technical nickel, hasbeen fused into it, one will frequentl find one or more, comparativelylarge an bubbles, which greatly lmpair the strength of the .jointbetween tooth and pin; frequently these bubbles will;

even be so large that the outer form of the tooth, suffers inconsequence by being bulged out. Even encased wires, consisting of 'acore wire of say technical nickel or some other metal or alloy with acovering of precious metal such as gold or platinum rolled on, will showthe same annoying phenomenon wherever this casing is in any respectunsound, for exampleat the point of the pin or at out surfaces.

Applicant has described in a separate .United States application SerialNumber 363,916, filed March 6, 1920, processes invented by himself, bymeans of which a sufficient degasificationof metals andmetal.

- ascertained, the respective metal can be obtained continuously withthe same good qualities by treating it at the said temperatures. I Forexample, an allow of nickel and chromium which had been melted accordingto the process forming the subjectmatter of the invention at a pressureof 1 mm. mercury column and 1440 (3., after previously showing a liberalevolution of gas, remains quite calm and apparently free of gases. When,subsequently worked, the.

metal showed bad quallties and tended to crack. The same alloy beingthen melted at varying pressures and temperatures, it was found that ata pressureof 3 mm. mercury column and a temperature of 1460 C.,, a

second very violent emission of gas occurred. The product of this meltwas, .on being worked, found to be perfect. All the numerous alloys ofthe same composition melted since that time were melted at 1460 C. and 13 mm. mercury column pressure.

- They all had a second emission of gas and subsequently showed all thesame unexpectedly good qualities.

r In all casesm which gases are emitted or produced during thesolidification the metal is viscousand in solid state not yet had been Iattained after the first melting.

i For example, an alloy of iron and cobalt will appear free of gas inthe molten state;

neither an increase of temperature nor a reduction of the pressure willbe able to cause a further emission of gas. 7 Only when solidificationsets in, a lively emission of gas commences and will continue until thealloy is fully solidified. An immediate re-melting will show neither afurther emission of. gas

during the melting nor from the molten metal, but only will allow theescape of the mechanically included gases of the first melting. Arenewed solidification liberates no more gas, and the product shows inevery respect freedom of gas flawless and good properties.

Extensive tests have shown that such metals remain free from gases, whenthey are subsequently worked or annealed in presence of various gasesand under various pressures. It has, in fact, been found, that infusing-in thin plates, sheets, rings, wires or the like, made of suchmetals or metal alloys, the fused 'oint remains fully free from bubbles,whic certainly means an important improvement in practice.

When the wires consist of a base metal core with a rolled on casing ofprecious metal, the said core is freed from gas in the same manner. Withthe precious metals employed as casing, viz platinum and gold, thisremoval of gas is unnecessary as these metals as a rule do not containany gases in solution, except of course if they are of insufficientpurity.

: What I claim is:

A ceramic metal joint comprising afine metal part composed of metalrendered substantially free from gas by successively remelting in asubstantially airtight furnace at different predetermined valuesoftemperature and reduced pressure, and a ceramic mass plasticallyclosed around said part while hot.

In testimony, that I claim the foregoing as my invei tion I have signedmy name this 27 dayof February 1920.

DR. WILHELM ROHN.

